Sealed beam lamp including filament locating means

Abstract

In a sealed beam incandescent lamp a generally concave reflector member is provided with three or more bosses having flat outer surfaces. The surfaces define a plane perpendicular to the axis of the parabola so that specific points within the parabola can be located with great precision. By using the bosses as reference points, lamp filaments can be accurately placed within the lamp structure, regardless of variations in the reflector member which occur during the manufacturing process.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 
     
       1. A sealed beam incandescent lamp, comprising: a lens member for refracting a beam of light emanating from within the lamp;   a generally concave reflector member attached to said lens member to form a lamp envelope, said reflector member exhibiting a substantially parabolic transverse section;   a filament assembly fixedly attached to said reflector member, and including a filament member disposed approximately in the latus rectum of the parabola; and   at least three discrete bosses formed in the inner surface of said reflector member, said bosses defining a plane substantially perpendicular to the axis of said parabola such that said bosses enable the accurate mounting of the filament at the latus rectum of the lamp.   
     
     
       2. A lamp according to claim 1, wherein said inner surfaces of said reflector member define spread light and light concentration areas for respectively dispersing and concentrating light from said filament, each of said bosses being disposed in a spread light area. 
     
     
       3. A lamp according to claim 2, wherein said bosses comprise discrete planar surfaces extending generally perpendicular to the axis of the parabola. 
     
     
       4. A lamp according to claim 3, wherein said plane defined by said bosses substantially coincides with the latus rectum of the parabola. 
     
     
       5. A lamp according to claim 4, wherein said reflector member terminates in a substantially circular periphery, and said bosses are disposed approximately 120° apart within said reflector member. 
     
     
       6. A lamp according to claim 4, wherein said reflector member terminates in a substantially rectangular periphery, there being at least four discrete bosses in said inner surface, each of said bosses being disposed adjacent a corner of the rectangle defined by the periphery of the reflector member.